in the mock debates, senator rob portman is playing barack obama. >> he's playing president obama in the mock debates we have. i don't like him very much anymore. >> reporter: as for president obama, he took a break from practice yesterday to visit a campaign office and make a few calls to unsuspecting voters. >> andrea? hi. this is barack obama. how are you? that's right. >> reporter: it was just a brief break for the president, who, like romney, has been rehearsing for days. senator john kerry is playing the role of romney in president obama's practice sessions. the campaign is managing expectations, saying last night, the president is out of practice. the last time he debated was four years ago. and, rob and paula, according to the latest abc news/"washington post" poll, 56% of americans expect president obama to win the debates. mitt romney told voters yesterday, that the debates are about more than who comes out on top. they are the chance for a month-long conversation with the american people. >> managing expectations, as always. tahman bradley, live in washington for us. thank